1. Field of the Invention
The present invention is concerned with the field of magnetic switches. In particular, the invention is concerned with a magnetic switch apparatus that detects relative movement between first and second members and defeats attempted external magnetic manipulation of the apparatus.
2. Description of the Prior Art
Prior art security alarm systems use magnetic switches attached to doors and windows and integrated with the system for detecting unauthorized opening indicating an intruder. One common type of magnetic switch is a so-called reed switch. This type of switch is subject to manipulation by an external magnet. That is, an intruder can use a magnet to hold the read switch closed (or open depending upon the control scheme) and thereby open a door or window without triggering the alarm system.